Have you asked on the Celebrity board, here:
https://boards.cruisecritic.com/forum/16-celebrity-cruises/
FAR more expertise and experience there. I expect this thread will be moved there.
Seas can be rough any time any location, and aren't predictable more than a few days in advance. ANY TIME you get on a ship you could encounter rough seas, thus you need to be prepared.
Quite likely it will be very warm and humid on your balcony, if you are out there for extended periods. @BillB48 gave you a good response, but I definitely think you are over analyzing this.
If you look, there are 3 threads in the first two pages of the board discussing Miami hotels. Price is going to be severely affected by when you are going...an important factor.
Hampton Brickell is a great hotel in an excellent location. Recommended here very frequently.
To start with, you absolutely need to do some reading...there are many cruise lines out there to choose from. I have never sailed on a cruise where you had to pay for a show...I think that is just one cruise line. Many of the other things you note appear to me to be mostly limited to one cruise line.
Hank, a round trip out of a US port, in this example, Boston, can visit a foreign port to meet the PVSA requirements. The 'distant foreign port" requirement does apply to the concept of a roundtrip out of Boston, or New York or similar for a New England cruise. Just like Alaska cruises, or Caribbean cruises, or Mexican Rivera cruises.
The better place for your question would be the Florida Departures Board, here:
https://boards.cruisecritic.com/forum/386-florida-departures/
There are MANY other options over there, the common one being shuttle services, and Uber/Lyft to either the port, or to a hotel near the port, which will have shuttle services to the port.
Welcome to Cruise Critic!
There are a number of laws about this. There maybe one or two small, specialized cruise lines that can do it, but generally, the laws require a stop in a foreign country for a roundtrip cruise out of a US port. So, in this case, there would need to be at least one Canadian port.
What appears to be "unfilled" could simply be unassigned, but sold on Guarantee bookings.
Many threads here saying recently GTY bookings are filled around 8-10 days prior to sailing.
The side of the ship doesn't matter.
For all the MSC info you will ever need, take a look at the MSC board, here:
https://boards.cruisecritic.com/forum/49-msc-cruises/
Take a look at the Italy board, here:
https://boards.cruisecritic.com/forum/464-italy-ports/
Many discussions there. The Mods may move it there as it doesn't have anything to do with HAL.
I am sorry, but this is still confusing. Your post title says "post cruise". So you want to stay and do things in Seward for a few days post cruise, then eventually need a transfer to the Anchorage airport?
There several threads here discussing your Seward to Anchorage options...train, bus, for example.
I would start by reading on the NCL board, here:
https://boards.cruisecritic.com/forum/64-norwegian-cruise-line/
Where you will find all the NCL info you will ever need.
Check out the Med Ports boards, here:
https://boards.cruisecritic.com/forum/8-europe/
To find out what others on your cruise are doing, look here:
https://boards.cruisecritic.com/forum/307-norwegian-gem-roll-calls/